Discharge device



Feb. 21, 1961 a. RosENERG 2,972,

DISCHARGE nsvzcs Filed Feb. 25. 1959 2 Sheets-Sheet 1 INVENTOR EflE/VETI' FGfE/VEE EE.

ATTURNEY Feb. 21, 1961 B. ROSENBERG DISCHARGE DEVICE 2 Sheets-Sheet 2 Filed Feb. 25, 1959 FIG.5.

INVENTOR. BFi/P/VEU' PQFEMEERG 2,972,693 DISCHARGE DEVICE Barnett Rosenberg, New York, N.Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 25, 195?, Ser. No. 795,545 16 Claims. (Cl. 313-408) This invention relates to discharge devices and, more particularly, to discharge devices having a color-corrected output. 7

Discharge devices such as high-pressure, mercury-vapor (HPMV lamps) are extensively used for outdoor and factory illumination. The efficiency of these devices in generating visible light is excellent and a high-power source can be made relatively small, thereby eliminating the need for an excessive number of fixtures. The light which is generated by such devices is concentrated primarily in the yellow and the green, which when blended together produce a generally white light. While the color of this light is not displeasing, the color rendition of objects illuminated by such light is not as good as desired. it has been disclosed in US. Patent No. 2,748,- 303 to Thorington, dated May 29, 1956, to color correct an HPMV lamp by placing a phosphor material on'the inner surface of the outer envelope which surrounds the arc tube. In addition to visible light, the arc tube source generates an appreciable amount of ultra violet radiations and infrared radiation. In accordance with this aforementioned patent to Thorington, the phosphor material converts generated ultraviolet radiations into red radiations, in order to color correct the output of the lamp and to improve the color rendition of objects which are illuminated by the lamp.- To be of practical use, the phosphor which is used to color correct such a. lamp must have good output at relatively high temperatures and most photoluminescent phosphors, that is those which will convert ultraviolet radiations into visible radiations, have a relatively poor output at such elevated temperatures. Thus the phosphor materials which are available to color correct discharge devices, such as HPMV lamps, are few in number. In addition, no phosphor is completely transparent with the result that some of the visible light which is generated by the mercury discharge source is absorbed as it traverses the phosphor. It is desirable to be able to color correct discharge devices such as HPMV lamps with various colors to supplement the visible light generated thereby. In addition, it is desirable to utilize substantially transparent materials for color correcting the visible light emitted by such discharge devices.

It is the general object of this invention to avoid and overcome the foregoing and other difiiculties of and objections to prior-art practices by the provision of a discharge device having an output which is color corrected, in order to improve the appearance thereof and to irnprove the color rendition of objects illuminated thereby.

It is a further object to provide a high-pressure, mercury-vapor discharge lamp, the normal light output of which can be color corrected with a variety of colors in such manner that substantially no visible light as normally generated by the lamp is absorbed.

It is a further object to provide various constructional embodiments for such a discharge device as well as vari- :ous materials which can be used to color correct such a discharge device.

The aforesaid objects of the invention, and other objects which will become apparent as the description proceeds, are achieved by providing an additional envelope pro im he are tube of a ischarge device. such. as

2,972,693 Patented Feb. 21, 196i '2 an HPMV lamp. This additional envelope contains a quantity of selected organic material which at a selected range of elevated temperatures and under ultraviolet irradiation exists as a stable fluorescent gas. The size and location of this additional envelope with respect to the power input to the arc tube discharge source are so selected that when the source is operated, the tempera{ ture extremes encountered within the additional envelope fall Within the-selected temperature range at which the organic material exists as a stable fluorescent gas.

For a better understanding of the invention, reference should be had to the accompanying drawings 'wherein: Fig. l is an elevational view, partly in section, illustrating an HPMV lamp constructed in accordance With this invention;

Fig. 2 is a sectional view taken on the line II-II in Fig. l in the direction of the arrows, illustrating con.- structional details for the additional envelope which is utilized;

Fig. 3 is a perspective view of the additional envelope which is placed intermediate the arc tube and the outer .envelope of the HPMV lamp as shown in Fig. l;

Fig. 4 is a perspective view illustrating an alternative embodiment for the additional envelope as utilized, whereby a plurality of small additional envelopes are adapted to be positioned intermediate the arc tube and the outer envelope of the device as shown in Fig. 1;

Fig. 5 is an elevational view, partly in section, illustrating another alternative discharge device constructed in accordance with the present invention;

Fig. 6 is an elevational View, partly in section, illustrating still-another alternative discharge device constructed in accordance with the present invention.

Although the principles of the invention are broadly applicable to any metal-vapor discharge device of any size, the invention is conveniently employed in conjunc tion with a high-pressure, mercury-vapor lamp designed to operate with a power input of 400 watts, and hence it has been so illustrated and will be so described.

With specific reference to the form of the invention illustrated in the drawings, the numeral 19 in Fig. 1 indicates generally a high-pressure, mercury-vapor lamp comprising an inner arc tube 12 supported by a metal arc-tube mount 14 within an outer envelope 16. An additional envelope 18 is supported intermediate the arc tube 12 and the outer envelope to and this additional envelope contains a quantity of selected organic material as will be described in detail hereinafter. Except for the additional envelope 18 and supporting means therefor, the device 10 as shown in Fig. 1 is generally conventional. The are tube 12, which in the embodiment as shown is adapted to be operated with a power input of 400 watts, is comprised of a quartz tube 20 having operating electrodes 22 electrical= ly connected to conventional ribbon conductorszd sealed through either end of quartz tube 20. Adjacent one of the electrodes 22 is a starting electrode 26, which electrically connects through a starting resistor 28 to that electrode 22 which is deposed at the opposite end of the arc tube 12. The arc-tube mount 14, which supports the arc tube 12 within the outer envelope 16, includes two rod-like supports 39 which are electrically connected to a supporting lead conductor 32 and one of the electrodes 22. The lead conductor 32 is hermetically sealed through a conventional reentrant stem 34 and electrically connects to the base 36 of the lamp 10. The other electrode 22 of the arc tube 12 is electrically connected to a second lead conductor 38, which also electrically connects to the base 36. Additional traverse supports All are aflixed to the rod-like supports 30 at the upper end of the outer envelope 16 in order to inhibit any relative movement of the arc-tube mount 14. The foregoing construction is V 2,972,693 A f generally conventional and other known are tube mounts can be substituted therefor.

In the preferred form of the present invention, the additional envelope 18 as shownin Figs. 1, 2 and 3 is positioned intermediate the arc tube 12 and the outer envelope 16 and preferably has a hollow cylindrical configuration. In order to facilitate positioning of this additional envelope 18, additional channel supports 42 are provided at either end of the envelope 18and these channel supports are supported by retaining rings 44 which are welded'to the rod-like supports 30. The channel supports 42 can be fabricated of metal or ceramic, the latter material providing better insulation against conductivity of heat from the rod-like supports 30 to any discrete portions of the additional envelope 18. Contained within the additional envelope 18 is a quantity of organic material which at a selected range of elevated temperatures and under ultraviolet irradiation exists as a stable fluorescent gas. extremes which are encountered .within the additional envelope 18 within the selected range of elevated tempera- .tures at which the organic material exists as stable fluorescent gas, the size and location of the additional envelope 18 are selected with respect to the size and location of the source and the power input thereto. The size and location of the outer envelope 16 is to a lesser degree an additional factor which determines the temperature ex- .tremes encountered within the additional envelope 18.

' fluorescence.

In order to maintain the temperature For the specific example as described hereinbefore, the

arc tube 12 has a power input of 400 watts, a length of 89 mm., a diameter of 16.5 mm, and a spacing between operating electrodes of 70 mm. Contained within the arc tube 12 is 66 mg. of mercury and argon at a pressure of 22 mm. The bulbous portion of the outer envelope 16 .has a total length of 156 mm. and a maximum diameter of .118 mm.. With such a construction, the intermediate envelope 18 can be formed of quartz having a thickness of 1 mm., a total length of 70 mm., an outside diameter of .54 mm. and an inside diameter of 42 mm.

The organic compounds which can be included in the intermediate envelope 18 are selected polycyclic organic substances or materials Which at a selected range of elevated temperatures and under ultraviolet irradiation exist as stable fluorescent gas. Following is a table, designated Table I, in which are listed some of the suitable organic compounds which can be used, along with the operative temperature range within which these materials exist as a stable gas, the range of ultraviolet excitation to which these materials respond and the resulting emissioncolor. 7 Table I O erative Responsi e Compound Temnera- Rance of Emission Color ture Range U.V. Ex- 0. citation A.U. Zethrene 400-700 iYellow-Green.

3,600 Ovalene..-. 500-700 }Yellou. 1,12, Benzperylene 450-700 }l3lue 3,4,Benzpyrene 450-700 }B1ue V 4,10,Dlan1inoPerylene- 450-700 }Blue Green.

Porphyrin 500-600 }Red. Naphthacene 450-700 }Green. Peryleneuu 350-700 }Blue. Decacycleno 450-700 iGreen-Whlte. Perylene, 3, 4, 9, 10, Tet- 2537 rgrriairboxyhc Dianhy- 400-700 3650 Yellow-Green.

Blue-White m mm 550-700 i; transient:

v ature range). coronene 500-700 }Bluel v '4 The foregoing listing of suitable organic compounds is quite extensive, but is not meant to be limiting, and other compounds with similar operating characteristics can be substituted therefor. These indicated materials can be admixed if desired or used singly within the additional envelope 18. Of the foregoing compounds, those which are preferred are perylene, decacyclene, fluoranthene, coronene and 3, 4, benzpyrene. The quantity of organic material is in no way critical and can be varied over a wide range. There should be suificient material, however, so that its effect is detectable, although even trace amounts of these organic materials will exhibit some detectable As a specific example, 1 milligram of perylene can be used in the additional envelope 18 of the foregoing lamp as described. In some cases, it may be desirable to include with the indicated organic fluorescent material in the envelope 18, a small amount of additional stable organic compound such as 0.1 milligram of napthalene for example. Such additional compound when vaporized acts to stabilize the foregoing polycyclic organic fluorescent material to inhibit any tendency for degradation, which might result from slightly-excessive temperatures.

In Fig. 4 is shown in perspective view an alternative additional envelope embodiment 46, which can be substituted for the additional envelope 18 as shown in Figs. l-3. Briefly, this envelope embodiment 46 comprises a plurality of small elongated envelopes 48 which are retained in position by suitable metallic mounting sleeves 50. The mounting sleeves 5t] are adapted to be retained in position on the rod-like supporting members 30 by means of punched retaining slots 52 provided therein. Each of the small individual envelopes 48 can contain one organic fluorescent material or mixtures of the foregoing organic fluorescent materials. Alternatively, different organic fluorescent materials can be provided in some or all of the individual envelopes 48 if desired, in order to provide color blends.

In some cases, it is desirable-to include a suitable filter means between the arc tube 12 and the additional envelope 18 or 48 inorder to shield 1856 AU. and other shortwave ultraviolet radiations from the organic ma terial. In such a construction, the additional envelope can be fabricated of material which is opaque to radiations having a wavelength of less than about 2537 A.U., such as glass marketed under the trademark Vycor by Corning Glass Works, Corning, New York. Alternatively, an additional sleeve of such selective filtering glass can be provided intermediate the additional envelope 18 and the inner arc tube 12.

All of the foregoing organic materials as listed are substantially transparent when in the gaseous state although porphyrin has some absorption in the shorter wavelength region. In the operation of the lamp as described hereinbefore, the visible radiations which are normally generated by the discharge source are supplemented by the fluorescent response of the organic material, in order to supplement and color correct the light which is normally emitted by the discharge source.

In Fig. 5 is shown an alternative device embodiment 54 wherein the arc tube discharge source 12 is surrounded by a double envelope 56. The selected organic fluorescent material as indicated hereinbefore is contained within-the double envelope 56. The are tube 12 and are tube mount 14 can be fabricated as in the embodiment 10 shown in Fig. 1 and the additional double envelope 56 has such size and location with respect to the arc tube 12 that when the arc tube discharge source is operated, the temperature extremes encountered within the additional double envelope as fall within the selected temperature range at which the indicated organic substance exists as a stable fluorescent gas. The additional double envelope 56 is maintained in position by a hollow-cylindrical, insulating support member 53 which is partially closed'at its lower end and is supported in turn by the upper end of the lamp base 36.

A further alternative lamp embodiment 60 is shown in Fig. 6. With respect to the arc tube 12, are tube mount 14 and electrical connections thereto, this embodiment 60 corresponds to the embodiment it) as shown in Fig. 1. The enlarged outer envelope as utilized in the embodiment 10, however, is dispensed with and the arc tube 12 is surrounded by a relatively small outer or additional envelope 62. The selected organic substance is retained in the spacing which is intermediate the outer envelope 62 and the arc tube 12. In such an embodiment, it is necessary to operate the arc tube discharge source 12 at such power input that the maximum temperature encountered on the outer surface of the arc tube 12 does not exceed the maximum temperature at which the selected organic material exists asa stable fluorescent gas. a

While a mercury-vapor discharge source has been considered in detail in the foregoing description, it'should be understood that other metal-vapor discharge sources, such as zinc, cadmium or magnesium discharge sources, may be substituted for the mercury discharge source. It may be desired to operate these sources with lower power input in order to minimize the maximum temperatures which are generated, such as in connection with the embodiment 60 as shown in Fig. 6. In such a case, these sources can be operated at a pressure of about microns for example, under which conditions the foregoing selected organic materials will not be exposed to such temperatures as cause them to break down, even though they actually contact the outer surface of the discharge tube 12.

It will be recognized that the objects of the invention have been achieved by providing a discharge device having an output which is color corrected, in order to im prove the appearance thereof and to improve the color rendition of objects illuminated thereby. In addition, the normal light output of the discharge source can be color corrected with a variety of colors in such manner that substantially no visible light as normally generated by the source is absorbed. There have also been provided various constructional embodiments for the foregoing discharge device.

While best-known embodiments have been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

I claim:

1. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material cornprising a quantity of selected organic substance contained within said additional envelope; said selected organic substance at a selected range of elevated temperature and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that when said source is operated, the temperature extremes to which said selected organic substance is exposed fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

2. The combination which comprises: an envelope-enclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope surrounding said source; material comprising a quantity of selected organic substance contained intermediate said additional envelope and said discharge source; said selected organic substance at a selected range of elevated temperatures and under ultraviolet irradiation existing as additional envelope with respect to said'source being so selected that when'said source is operated, the terriperature extremes to which said selected organic substance is exposed fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

3. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope surrounding said source; material comprising a quantity of selected organic substance contained within said additional envelope and exterior to said discharge source; said selected organic substance at aselected range of elevated temperature and under ultraviolet irradiation existing as stable fluorescent gas; and the size'and location of said additional envelope with respect to said source being so selected that when said source is operated, the temperature extremes to which said selected organic substance is exposed fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

4. The combination Which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional double envelope positioned about said source; material comprising a quantity of selected organic substance con tained within said addiitonal double envelope; said selected organic substance at a selected range of elevated temperature and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional double envelope with respect to said source being so selected that when said source is operated, the temperature extremes encountered Within said additional double envelope fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas. Y Y

5. The combination which comprises: an envelopeenclosed ,high-pressure metal-vapor discharge source adapted to operate with a predetermined power input;

saidsource when operated emitting ultraviolet radiations,

infrared radiations and visible radiations; an outer enve lope surrounding said source; an additional envelope positioned intermediate said discharge source and said outer envelope; material comprising a quantity of selected organic-substance contained within said additional envelope; said selected organic substance at a selected range of elevated temperatures and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source and said outer envelope being so selected that when source is operated, the temperature extremes encountered within said additional envelope fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

6. The combination which comprises: an envelopeenclosed high-pressure mercury-vapor discharge source adapted to operate with a predetermined power input; said source When operated emitting ultravialet radiations, infrared radiations and visible radiations; an outer envelope surrounding said source; an additional envelope positioned intermediate said discharge source and said outer envelope; material comprising a quantity of selected organic substance contained within said additional envelope;

said selected organic substance at a selected range of elevated temperatures and under ultraviolet irradiation existing as stable fluorescent gas; and'the size and location of said'additional envelope with respect to said source and said outer envelope being so selected that when said source is operated, the temperature extremes stable fluorescent gas; and the size and location of said 7 encountered within said additional envelope fall within the selected temperature range at which said selectedorganic substance exists as stable fluorescent gas.

p 7. The combination which comprises: an envelopeenclosed high-pressure mercury-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an outer envelope surrounding said source; additional envelopes positioned intermediate said discharge source and said outer envelope; material comprising a quantity of selected organic substance contained within said additional envelopes; said selected organic substance at a selected range of elevated temperatures and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelopes with respect to said source and said outer envelope being so selected that when said source is operated, the temperature extremes encountered within said additional envelopes fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

8. The combination which comprises: an envelopeenclosed high-pressure mercury-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an outer envelope surrounding said source, an additional envelope positioned intermediate said discharge source and said outer envelope; material comprising a quantity of admixed selected organic substance contained within said additional envelope; said selected organic substance at a selected range of elevated temperatures and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source and said outer envelope being so selected that when said source is operated, the temperature extremes encountered Within said additional envelope fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

9. The combination which comprises: an envelopeenclosed high-pressure mercury-vapor discharge source adapted to operate with a predetermined powerinput; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an outer envelope surrounding said source; additional envelopes positioned intermediate said discharge source and said outer envelope; material comprising a quantity of selected or- .ganic substances contained within said additional envelopes; said selected organic substances at a selected range of elevated temperatures and under ultraviolet irradiation existing as stable fluorescent gas; and'the size and location of said additional envelopes with respect to said source and said outer envelope being so selected that when said source is operated, the temperature extremes encountered within said additional envelopes fall within the selected temperature range at which said selected orperylene; decacyclene; perylene, 3,4,9,10, tetracarboxylic i-dianhydride; fluoroanthene; coronene; 1,12 benzperylene;

3,4, benzypyrene; 4,10, diamino perylene; prophyrin; naphthacene; zethrene and ovalene; said selected organic substance at a selected range of elevated temperature and .under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that when said source is operated, the temperature extremes to which said selected organic substance is exposed fall within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

11; The combination which comprisesran envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising a quantity of perylene contained within said additional envelope; said perylene at a temperature of from 350 C. to 700 C. and under ultraviolet irradiation ex isting as stable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that when said source is operated, the temperature extremes to which said perylene is exposed fall within the selected temperature range at which said perylene exists as stable fluorescent gas.

12. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising'a quantity of decacyclene contained within said additional envelope; said decacyclene at a temperature of from 450 C. to 700 C. and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that when said source is operated, the temperature extremes to which said decacyclene is exposed fall within the selected temperature range at which said decacyclene exists as stable fluorescent gas.

13. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising a quantity of fluoranthene contained within said additional envelope; said fluoranthene at a temperature of from 550 C. to 700 C. and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising a quantity of coronene contained within said additional envelope; said coronene at a temperature of from 500 C. to 700 C. and under ultraviolet irradiation existing asstable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that when said source is operated, the

temperature extremes to which said coronene is exposed fall within the selected temperature range at which said coronene exists as stable fluorescent gas.

15. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with .a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising a quantity of 3,4, benzpyrene contained within said additional envelope; said 3,4, benzpyrene at a temperature of from 450 C. to 700 C. and under ultraviolet irradiation existing as stable fluorescent gas; and the size and location of said additional envelope with respect to said source being so selected that whensaid source is operated, the temperature extremes to which said 3,4,

benzpyrene is exposed fall within the selected temperature range at which said 3,4, benzpyrene exists as stable fluorescent gas.

16. The combination which comprises: an envelopeenclosed high-pressure metal-vapor discharge source adapted to operate with a predetermined power input; said source when operated emitting ultraviolet radiations, infrared radiations and visible radiations; an additional envelope positioned proximate said source; material comprising a quantity of selected organic substance contained within said additional envelope; said selected organic substance at a selected range of elevated temperature and under ultraviolet irradiation existing as stable fluorescent gas; filter means positioned intermediate said when said source is operated, the temperature extremes to which said selected organic substance is exposed falls within the selected temperature range at which said selected organic substance exists as stable fluorescent gas.

References Cited in the file of this patent UNITED STATES PATENTS 2,748,303 Thorington May 29, 1956 

